Prior computer systems employ graphic interfaces to ease their use. Graphic interfaces allow a user to move a pointer on the monitor, via a mouse, to a demarcated "selectable area" of a monitor and click a mouse button or tap the enter key on a computer keyboard to execute a function associated with an image displayed by the area. Clicking the mouse button or tapping the enter key on the computer keyboard while the pointer is within a selectable area is known as "clicking on" the area. For example, a user may move a mouse pointer to an area displaying a disk icon and click on the area to open a window for displaying the contents of a disk represented by the icon.
Dialog boxes display messages to computer users and commonly employ buttons as a means of designating selectable areas. These designated selectable areas are known as buttons because they visually resemble the buttons on a control panel. When a dialog box is present on a computer monitor, no other function can be performed by the computer until the user clicks on the "OK" button within the dialog box, signifying that she has read the dialog message. Typically, the function associated with an "OK" button is simply going back to whatever application program was running before the dialog message was displayed to the user.
Buttons of the type used in dialog boxes are not suitable for all application programs because these buttons "lock up" the computer until the user clicks on a button. Furthermore, traditional buttons obscure the text and images beneath the button on the monitor. Finally, when it is desired to have many selectable areas, displaying many buttons simultaneously distracts the user by cluttering the monitor.
Some application programs allow the user to choose among a number of functions displayed on a menu bar located at the top edge of the monitor or displayed on a pull-down menu. While menus have an advantage over buttons because they do not continuously obscure text on the monitor, a function entry on a menu is disassociated spatially from the text associated with the function.